Esters and lactones, produced from acyclic and cyclic carboxylic anhydrides, have utility as intermediates in various dye, pharmaceutical and agricultural chemical syntheses, as well as in the production of lacquers, paints, varnishes and plasticizers, see, e.g., Kirk-Othmer, Encyclopedia of Chemical Technology (3rd Ed.), vol. 9, page 321. Lactones, in particular, are useful in polymerization processes, i.e., ring-opening polymerization, Encyclopedia of Polymer Science & Engineering, Vol. 12, pages 36-40 (2nd Ed.).
Currently, however, known processes for the production of esters or lactones from acyclic and cyclic carboxylic anhydrides require expensive catalysts, solvents that are expensive and/or difficult to handle, or both. Supplement B, The Chemistry of Acid Derivatives--Part 1, J. Wiley & Sons, New York, Chapter 7, reviews the synthesis of esters; ibid., Part 2, pages 1138-1145, reviews the reduction of anhydrides.
P. R. Austin et al., J. Am. Chem. Soc., 1937, 59; 864, disclose a method for the preparation of phthalide from phthalic anhydride by hydrogenation over a copper chromite catalyst at 270.degree. C. and 20.7-24.1 MPa of hydrogen, in the absence of a solvent, obtaining phthalide in 15 to 56% yield.
U.S. Pat. No. 4,485,245 and U.S. Pat. No. 4,485,246 to Lyons disclose a process for the homogeneous hydrogenation of phthalic anhydride to phthalide in unspecified yield.
U.S. Pat. No. 4,211,711, to Fuenten et al., discloses a method for the preparation of phthalide by the catalytic hydrogenation of a phthalide substituted in the 3-position by a hydroxy, methoxy or acetoxy group. The patent employs a group VIII metal catalyst in an inert organic solvent, preferably an alcohol, and obtains a product in up to 99% yield.
U.S. Pat. No. 4,528,385, also to Fuenten et al., discloses a method for the preparation of phthalide in 85% yield from phthalic anhydride using a nickel catalyst and a benzoic acid ester as the solvent. The reaction takes place at 150.degree. C. and 3.0 MPa of hydrogen.
British Patent No. 467,656 discloses catalytic hydrogenation of a phthalic anhydride to phthalide using a hydrogenating metal associated with an acidic oxide of (for example) titanium, preferably in a lower state of valency. They also disclose the presence of a solvent to be essential to high conversions.
U.S. Pat. No. 4,772,729 discloses preparation of 3-substituted tetrahydrofuran and 3- and 4-substituted butyrolactones by hydrogenating appropriate precursor materials in the presence of a catalyst containing palladium, rhenium and at least one support which is titanium dioxide, zirconium oxide or carbon.
U.S. Pat. No. 4,782,167 discloses preparation of butyrolactones and butane diols by hydrogenating the appropriate precursor in the presence of a catalyst containing palladium or palladium/rhenium on a titanium, zirconium or hafnium oxide support.